That amount of mass will push the arm/stylus resonant frequency down too low making the system unstably sensitive to external vibrations.
Kal
Kal
Tonearm: How much mass is too much?
For fun and education, I want to make a tonearm. How much mass is too much? Does the answer change with whether it is a gimble design or a unipivot design?
I guess that some mass is desirable to provide resistance to the movement of the cantilever, so that its energy is put into sound waves rather than arm movement. To use an extreme example, you could design a tonearm weighing 10lbs that when counter-weighted has a tracking force of 1.6 grams. However, I imagine the stylus would have a very difficult time dragging that mass along the grooves, both in the horizontal and vertical planes.
So, can anybody recommend or point me to a starting place on the topic of how much tonearm mass is useful?
thanks, Jeff
I guess that some mass is desirable to provide resistance to the movement of the cantilever, so that its energy is put into sound waves rather than arm movement. To use an extreme example, you could design a tonearm weighing 10lbs that when counter-weighted has a tracking force of 1.6 grams. However, I imagine the stylus would have a very difficult time dragging that mass along the grooves, both in the horizontal and vertical planes.
So, can anybody recommend or point me to a starting place on the topic of how much tonearm mass is useful?
thanks, Jeff
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Expanding on what Kr4 said, the ideal tonearm effective mass depends on which cartridge you mount on it. The cartridge's own mass affects the calculation. The compliance of the cartridge's suspension is an even larger factor. So there's no simple answer. A tonearm is one half of a mechanical system that includes the cartridge. Without knowing the parameters of one half it's impossible to optimize the other. One interesting concept relating to your question is the idea of differentiating between moving mass in the vertical vs. horizontal planes. High mass in the vertical plane is very bad for negotiating warps. High mass in the horizontal plane can, depending on the cartridge, help the arm resist deflection and improve bass and dynamics (just as you supposed). This is the theory behind the Dynavector tonearm. Look it up. Read the Strange Tonearm Tweak thread for a thorough education. |